Even if two proxies are from the same product, country, or data center, they may not deliver exactly the same speed.
This is because the same location does not necessarily mean the same network route. Different IP addresses can belong to different IP ranges or use different upstream networks, which may result in different routing paths between the proxy server and your local ISP.
This is especially noticeable for users in mainland China, where international routing quality can have a major impact on actual performance.
Several factors may cause the difference:
• Different routing paths: Two IPs in the same data center may take different upstream routes when sending traffic back to your network.
• Asymmetric routing: The route from you to the proxy and the route from the proxy back to you can be completely different. Download performance is particularly affected by the return path from the proxy server to your network.
• Network congestion: Even when two routes use the same carrier, they may pass through different interconnection points. One path may have plenty of available capacity while another becomes congested, especially during peak hours.
• Routing changes over time: Internet routes are dynamic. An IP that performs well during the day may perform differently during evening peak hours.
For example, two US proxy IPs from the same location could have similar latency, while one reaches 80 Mbps and another only reaches 20 Mbps because their actual return routes, congestion levels, or packet loss are different.
Therefore, a large speed difference between two otherwise similar proxy IPs does not necessarily mean that one of them is being speed-limited. In many cases, the difference comes from the network path between the proxy and your ISP.
